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  • #76
    Originally posted by Leftseat86 View Post
    I imagine it's not that difficult in the aforementioned aircraft. The wheel only tells you it's moving, not where it's set.
    What is this telling you?
    Or were you referring to the 737?

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    • #77
      Originally posted by Evan View Post
      What is this telling you?
      Or were you referring to the 737?
      Though apparently in the same place on those Airbus...the wheel with the stripes is still only giving you movement, the indicator next to it tells you where you are. That's what I meant. The indicator with an arrow or line is found on almost every airplane with a trim system. That is what one would use for determining exactly how the airplane is trimmed.

      Sorry to be pedantic.

      Comment


      • #78
        Originally posted by Leftseat86 View Post
        For what this is worth (probably f*ck all) whenever trimming in flight simulator or wondering about where the trim is set, I always look at the TRIM INDICATOR.

        I imagine it's not that difficult in the aforementioned aircraft. The wheel only tells you it's moving, not where it's set.
        The problem is not when YOU are trimming but when the automation is trimming "in the background".

        When the black wheel with white stripes and that makes a very clear and distinctive whining and clacking noise turns, that's a good prompt to look at the trim indicator. And even if you don't look at the indicator, if you see and listen the wheel turning for a few seconds and the plane suddenly pitches up as the result of that and you disconnect the AP and struggle to push down, it is more likely that, instead of saying "What is it doing now?" and keep fighting with the elevator, you will say "Why was it trimming up?" and trim down to help.

        --- Judge what is said by the merits of what is said, not by the credentials of who said it. ---
        --- Defend what you say with arguments, not by imposing your credentials ---

        Comment


        • #79
          Originally posted by Gabriel View Post
          The problem is not when YOU are trimming but when the automation is trimming "in the background".

          When the black wheel with white stripes and that makes a very clear and distinctive whining and clacking noise turns, that's a good prompt to look at the trim indicator. And even if you don't look at the indicator, if you see and listen the wheel turning for a few seconds and the plane suddenly pitches up as the result of that and you disconnect the AP and struggle to push down, it is more likely that, instead of saying "What is it doing now?" and keep fighting with the elevator, you will say "Why was it trimming up?" and trim down to help.
          I don't disagree with that at all, I just think for myself I would go "why do I have to fight the elevator so much *check trim indicator* why am I at +24? *trim down + relax elevator*...

          Again this is just flight simulator and limited piper/cessna flying talking. Fighting with the elevator in general should make it obvious you're trimmed exceptionally one way or the other...

          having the visual cue that the airplane is trimming itself wildly and continuously obviously has some value, but I don't see it being really much more difficult to figure things out without it...

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          • #80
            Originally posted by Leftseat86 View Post
            having the visual cue that the airplane is trimming itself wildly and continuously obviously has some value, but I don't see it being really much more difficult to figure things out without it...
            You can theorize all you want, but reality has cases like these:



            Note: Trying to fight confirmation bias, also in the 737, with its twin big and noisy trim wheels, there have been cases where the plane was trimming up more and more without the crew noticing. The two cases I know (an accident and an incident) resulted in a stall during an ILS approach after the AT retarded the throttles and the AP attempted to keep the glide slope with deteriorating speed. Turkish was one of them.

            --- Judge what is said by the merits of what is said, not by the credentials of who said it. ---
            --- Defend what you say with arguments, not by imposing your credentials ---

            Comment


            • #81
              Wait.. you're both confusing me. When that black and white trim wheel on the A320 is turning, the scale is turning with it; it's attached. So, If you are pushing on the elevators and not getting results, a quick peripheral glance to the trim wheel scale is going to show you green (below 7° NU) or not green (above 7° NU), and not green means trim it back to green (in a pinch). I know that not the purpose of the green band, but it should get you out of trouble without requiring close concentration on it.

              Originally posted by Leftseat86
              I don't disagree with that at all, I just think for myself I would go "why do I have to fight the elevator so much *check trim indicator* why am I at +24? *trim down + relax elevator*...

              Again this is just flight simulator and limited piper/cessna flying talking. Fighting with the elevator in general should make it obvious you're trimmed exceptionally one way or the other...

              having the visual cue that the airplane is trimming itself wildly and continuously obviously has some value, but I don't see it being really much more difficult to figure things out without it...
              That seems perfectly reasonable to me as well. Gabriel, I think the fact that just about every new airframe has gone to a silent pitch trim control confirms that assumption. It should be quite instinctive to a qualified pilot that ineffective elevator means check the trim.

              Comment


              • #82
                Originally posted by Gabriel
                You can theorize all you want, but reality has cases like this terrifying stall maneuver...
                Holy hammerhead, Batman.

                While I'm sure they went to full power, I see that the nose was a bit lower than optimum climb attitudes for some of the recovery.

                I know there are worse flights to not be on, glad I wasn't on that one either!
                Les règles de l'aviation de base découragent de longues périodes de dur tirer vers le haut.

                Comment


                • #83
                  Originally posted by Evan View Post
                  Wait.. you're both confusing me. When that black and white trim wheel on the A320 is turning, the scale is turning with it; it's attached. So, If you are pushing on the elevators and not getting results, a quick peripheral glance to the trim wheel scale is going to show you green (below 7° NU) or not green (above 7° NU), and not green means trim it back to green (in a pinch). I know that not the purpose of the green band, but it should get you out of trouble without requiring close concentration on it.
                  I think that the trim scale is not attached to the trim wheel but with a gear in between. I don't know in the A320, but typically it requires several full turns of the trim wheel to move the trim from one extreme to the other.

                  That's because it requires very fine tuning to get the right trim of an airplane at cruise. The faster the airspeed, the more sensible the plane is to a given deflection of the stabilizer (or any control surface).

                  In the 737, for example, a quick "click" of the thumb trim switch will make the wheel move like half a turn at once. Change the flaps config one notch and while on AP you'll have the wheel turn several turns to re-trim for the new config.


                  That seems perfectly reasonable to me as well. Gabriel, I think the fact that just about every new airframe has gone to a silent pitch trim control confirms that assumption. It should be quite instinctive to a qualified pilot that ineffective elevator means check the trim.
                  I agree. But accidents happen when things don't go as they should.
                  A pilot should not forget to lower the landing gear. After all, you have the required action of lowering the gear, the before landing checklist, and the stabilized approach gate, all points that should ensure that the gear is down. However, just in case, let's add a gear warning, and just in case, let's add a gear mode to the GPWS too.

                  In my opinion, ineffective elevator (for whatever reason) where the trim was NOT used (for no other reason than nobody up there thought of using it) has resulted in enough accidents and very serious as to give this issue a re-thought. Not that anybody will listen my rant, though, as they did with my stall rant

                  --- Judge what is said by the merits of what is said, not by the credentials of who said it. ---
                  --- Defend what you say with arguments, not by imposing your credentials ---

                  Comment


                  • #84
                    Originally posted by Evan View Post
                    It should be quite instinctive to a qualified pilot that ineffective elevator means check the trim.
                    Or do you mean, "It should be quite instinctive to a qualified pilot that ineffective elevator means check the trim wheel which works just like it does on almost all aircraft including the C150 from your initial flight training?".

                    ...and let's not forget: Ineffective elevator means maybe someone left the control locks in (check this forum for another active thread).

                    Ineffective elevator means that maybe the engine shredded all three hydraulic lines.

                    Ineffective elevator means that maybe the cargo door blew and the floor settled on the elevator cables.

                    Ineffective elevator means that maybe the control cable touched the positive battery terminal and froze there.

                    Ineffective elevator means that maybe the control cable came loose.

                    Ineffective elevator means that maybe the elevator itself has come loose.

                    Ineffective elevator means that maybe a rock kicked up from the runway and jammed the elevators.

                    Ineffective elevator means that maybe they rigged the plane a little off from where it should be and this is the first flight where the CG is this far aft.

                    Ineffective elevator means that maybe an inspection panel fell off.

                    Ineffective elevator means that maybe your other pilot is pulling up the whole time.

                    Ineffective elevator means that maybe you are going too fast and tucking over.

                    Ineffective elevator means that maybe you are in a deep stall and the tail is blanked out.

                    Ineffective elevator means that maybe a bunch of heavy-ass tanks have rolled to the back of the plane.

                    That's a lot of maybes when your plane is stalling itself (or not pulling up) at altitudes from which you have marginal ability to recover.
                    Les règles de l'aviation de base découragent de longues périodes de dur tirer vers le haut.

                    Comment


                    • #85
                      Originally posted by Gabriel View Post
                      You can theorize all you want, but reality has cases like these:
                      "Ladies and gentlemen, you are kindly requested to remain calm and keep your seat belts fastened really really tightly..."
                      Be alert! America needs more lerts.

                      Eric Law

                      Comment


                      • #86
                        Originally posted by elaw View Post
                        "Ladies and gentlemen, you are kindly requested to remain calm and keep your seat belts fastened really really tightly..." You can clean the vomit later.
                        Fixed!

                        There was another very similar case that also had an animation, but I could not find it.

                        --- Judge what is said by the merits of what is said, not by the credentials of who said it. ---
                        --- Defend what you say with arguments, not by imposing your credentials ---

                        Comment


                        • #87
                          Trying to fight confirmation bias, also in the 737, with its twin big and noisy trim wheels, there have been cases where the plane was trimming up more and more without the crew noticing. The two cases I know (an accident and an incident) resulted in a stall during an ILS approach after the AT retarded the throttles and the AP attempted to keep the glide slope with deteriorating speed. Turkish was one of them.
                          This goes back to my earlier question - have the 'nose up pitch' incidents been confined to aircraft without a trim wheel, or do we see just as many incidents when it is there as when it is not there?

                          Comment


                          • #88
                            Originally posted by MCM View Post
                            This goes back to my earlier question - have the 'nose up pitch' incidents been confined to aircraft without a trim wheel, or do we see just as many incidents when it is there as when it is not there?
                            I saw your question back them.
                            The answer to the first one is "no", upsets due to miss-trim happened in both categories.
                            The answer to your second question is "I don't know". We'll need to have number of incidents, hours flown in each type, etc....

                            But I am coherent with myself. I want the yokes/sticks to be linked, to move when the AP makes control inputs, the TLs to move when the AT makes power adjustments, and the trim wheel to move when the AP (or other automation) trims. In fact, I have an idea since many many years ago, Since I flew the Tomahawk, the Cessna 152, a Cherokee, and an Aero Boero, that use 4 different elevator/trim approaches. Form those, I objected the Aero Boero style. For the person not familiar with this plane, it looks similar to a Piper Cub, and has the same type of elevator/trim solution.

                            Who cares to guess?

                            --- Judge what is said by the merits of what is said, not by the credentials of who said it. ---
                            --- Defend what you say with arguments, not by imposing your credentials ---

                            Comment


                            • #89
                              Originally posted by Gabriel View Post
                              I think that the trim scale is not attached to the trim wheel but with a gear in between. I don't know in the A320, but typically it requires several full turns of the trim wheel to move the trim from one extreme to the other.
                              Yes, I mean the scales are geared and move with the wheels, so they always provide an indication of pitch trim although I think the trim wheel only turns about 2x to move the scale 1x. It's a lot smoother, not jerking around like the 737. I'm not sure but I thought Leftseat86 was implying that only the wheels move to show pitch trim is in motion without the scale moving as well. At any rate, it is perfectly obvious that the trim is moving.

                              CHeck out the green band on this vdeo (just after the landing touchdown). Skip ahead to about 2:20: https://www.youtube.com/watch?v=_CQo2uybkNg

                              In my opinion, ineffective elevator (for whatever reason) where the trim was NOT used (for no other reason than nobody up there thought of using it) has resulted in enough accidents and very serious as to give this issue a re-thought. Not that anybody will listen my rant, though, as they did with my stall rant
                              Yes, it needs to be ingrained more in training. The wheel is history Gabe.

                              Comment


                              • #90
                                Originally posted by Gabriel View Post
                                In my opinion, ineffective elevator (for whatever reason) where the trim was NOT used (for no other reason than nobody up there thought of using it) has resulted in enough accidents and very serious as to give this issue a re-thought. Not that anybody will listen my rant, though, as they did with my stall rant
                                What about a an aural / visual warning like "PITCH TRIM" when the trim goes to an extreme outside the usual range?

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